Document Detail


The effect of a carbohydrate beverage on the physiological responses during prolonged load carriage.
MedLine Citation:
PMID:  21234592     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Effects of a carbohydrate beverage on the physiological responses to load carriage were examined. Ten fit male participants (age: 28 ± 9 years, body mass: 81.5 ± 10.5 kg, VO(2max): 55.0 ± 5.5 mL kg(-1) min(-1)) completed two test conditions in random order, walking on a treadmill (6.5 km h(-1)) for 120 min, carrying a 25-kg backpack. At 0 and 60 min of exercise participants consumed 250 mL of a placebo (flavoured water) (PLA) or 6.4% carbohydrate (CHO) beverage. There were no differences in VO(2,) respiratory exchange ratio (RER), heart rate or EMG activity of m. rectus femoris, m. vastus lateralis, m. semitendinosus and m. biceps femoris between conditions at minute 5 of exercise. The increase in VO(2) between minutes 5 and 120 was less during CHO than PLA (8 ± 5 vs. 14 ± 6%, P = 0.036). RER decreased during PLA, from 0.96 ± 0.05 at minute 5 to 0.87 ± 0.04 at minute 120 (P < 0.001), but not during CHO (P = 0.056). Heart rate increased between minutes 5 and 120 during PLA (16 ± 10%, P < 0.001) and CHO (12 ± 6%, P < 0.001), with no difference between conditions (P = 0.251). EMG peak RMS did not change between minutes 7 and 107 during PLA or CHO for the leg muscles. However, individual responses in EMG were highly variable (i.e. both increases and decreases in RMS). It was concluded that carbohydrate intake during load carriage reduced the VO(2) drift, which could be partially attributed to higher carbohydrate oxidation rates. Despite muscle fatigue/damage previously being identified as a cause of VO(2) drift, it appears that carbohydrate had no effect on neuromuscular responses during load carriage.
Authors:
Sam D Blacker; Neil C Williams; Joanne L Fallowfield; Mark E T Willems
Publication Detail:
Type:  Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't     Date:  2011-01-14
Journal Detail:
Title:  European journal of applied physiology     Volume:  111     ISSN:  1439-6327     ISO Abbreviation:  Eur. J. Appl. Physiol.     Publication Date:  2011 Aug 
Date Detail:
Created Date:  2011-08-17     Completed Date:  2011-12-13     Revised Date:  2012-02-14    
Medline Journal Info:
Nlm Unique ID:  100954790     Medline TA:  Eur J Appl Physiol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  1901-8     Citation Subset:  IM    
Affiliation:
Department of Sport and Exercise Sciences, University of Chichester, College Lane, Chichester, West Sussex, PO19 6PE, UK. sam@optimalperformance.co.uk
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MeSH Terms
Descriptor/Qualifier:
Adult
Beverages*
Dietary Carbohydrates / pharmacology*
Exercise / physiology*
Exercise Test / drug effects*,  methods
Humans
Male
Muscle Fatigue / drug effects
Physical Exertion / drug effects
Placebos
Pulmonary Gas Exchange / drug effects,  physiology
Time Factors
Walking / physiology*
Weight-Bearing / physiology
Young Adult
Chemical
Reg. No./Substance:
0/Dietary Carbohydrates; 0/Placebos

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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